RT Journal Article
SR Electronic
T1 Discussion
JF Quarterly Journal of the Geological Society
JO Quarterly Journal of the Geological Society
FD Geological Society of London
SP 436
OP 441
DO 10.1144/gsjgs.122.1.0436
VO 122
IS 1-4
YR 1966
UL http://jgs.lyellcollection.org/content/122/1-4/436.abstract
AB Dr E. K. Walton said that it was most unsatisfactory to speak of Carboniferous cyclic sedimentation when it was obvious that the authors were not considering all types of cycle which occurred in that system. It should be made quite clear which cycles they were attempting to explain. He also objected to the use of ' cycle' in an apparently imprecise way. The authors gave little indication how, for example, a major cycle was picked out. Was there a clear distinction, as the authors implied, between their major and minor cycles? Was it not the case that very often separation of major and minor cycles was quite arbitrary? It was rather naïve to consider only two hypotheses concerning cyclic sedimentation and having disproved eustatic control, to their own satisfaction, to conclude that tectonic control must be the answer. There were several other possibilities, amongst which sedimentational control was favoured by many workers. Had the authors considered this possibility and what role did they suppose sedimentational factors played in the formation of the cycles?Professor W. D. Gill doubted if the cycles of sedimentation in rocks of deltaic association had any control from tectonic slope adjustments. The authors' examples seemed to lack adequate control of laterally equivalent non-cyclic sediments.Recent studies in the Lower Carboniferous Mullaghmore Sandstone Formation of north-west Ireland had shown a typical cyclic deltaic sequence round Mullagh-more and Kildoney (Co. Sligo and south Co. Donegal). In the southern areas of Co. Sligo, in Co. Cavan and Co. Leitrim,